Trying to make an old metal Ensoniq ESQ1 work again, after being stored for 20 years. Since the battery was empty, all the different sounds were gone - That's what happens on OS version 2.0, I've learnt. So I got hold of eproms with OS 3.5, since that would also restore the 40 original sounds. After changing battery and eproms, the esq1 does not boot up. Nothing works. I put back the old eproms, and it's back to the one default sound in all positions. So the thingy works, but the new eproms don't. So, the question I have for those with knowledge is: Is there a compatibility problem with the early version (metal) esq1 and the OS 3.5? Or is it likely to be a problem with the eproms I got?

No, it is 35 years since I worked with those. I got the proms ready made from italy. I'm now sending them back for double checking them.As the older metal version and the newer plastic version are quite differently built, I thought that there might be some difference that made the newest OS incompatible. But even if the layout is different, they can still be made with the same components and the same schematics.